husband denying

Every citizen can act as per his own wish and if not illegal.  Members are not aware of the facts and his constraints, except through convincing elders from his side or personally requesting him, there is no other legal way to compel him.  Any harsh step may further complicate things.  First focus on the recovery of your sister.

Hello,

Yes, you have to resolve the issue between husband and wife by discussion. You can involve the elder family members from both sides to find out an amicable settlement.

The circumstances quoted in the query are cruelty to the wife. There may be other incidents also. If the issue is not resolved then the wife can approach the court under the domestic violence act against the husband. 

Yes, in the given situation, legal steps may not be the ideal remedy.

Settle the issues amicably.

Law do not provide relief / remedy to moral or social support.